Mystery of a seemingly over carbonated keg

by Daniel on July 15, 2012

I kegged my most recent beer a few weeks ago and was excited to try it after giving it about 5 days to carbonate. To my dismay, when I went to pour the first glass it looked a lot like the photo on the right: all foam. The first thing that came to my mind was that I had over carbonated it. You’ll find out later as I did that this was not the case, but I had to find out by process of elimination!

I was confused because my “over carbonated” beer was hooked up to the same regulator & pressure as my American pale ale that was serving at just the right carbonation. Although this was the case, I couldn’t think of anything else at the time other than it being over carbonated – so I went about trying to correct the problem.

missing gasket

I was patient at first, laying the keg on its side for 15mins at a time, then standing it up and releasing some pressure, then repeating. When that didn’t work, I turned to YouTube. There, a guy explained how hooking up the CO2 at the desired new pressure to the “beer out” line of the keg and then releasing pressure from the top valve a few times for a few seconds each. When done to an over carbonated beer, you hear bubbling through the beer as new CO2 is pumped into the bottom of the beer and bubbles up. Do to some sort of reaction, extra CO2 comes out of solution from your beer and is released as you open the valve at the top.

installing the gasket

Unfortunately, this did not work. Back to square one. What else could possibly be wrong? I was pretty confident at this point that I had eliminated the over carbonation problem. Next, I thought that maybe my picnic tap or ball-lock attachment was bad. After hooking up one that I knew was good and getting the same result, that quickly eliminated that possibility. Next logically in my mind was something with the keg itself. So I took apart the ball-lock attachment on the “beer out” line and immediately found my problem. I was missing the rubber gasket from the dip tube! Without this providing providing the proper seal, it was allowing gas out along with just a little of my beer – leading to all the foam. As soon as I replaced the gasket, the problem was solved. So when you first buy your kegs and disassemble them and clean them, make sure you don’t miss a gasket like I did. The reason I hadn’t caught it earlier even though I had found the gasket after reassembling the kegs was that I was convinced that the gasket was missing from the keg containing my American pale ale, which was serving just fine and I planned to replace the gasket once I kicked the keg.